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2015-11-17 13:59:55
diesel advanced systems

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  1. Conditions required for manual synchronized closure of D/G output breaker?
    • Generator overcurrent/differential current lockout relay reset
    • No bus overcurrent lockout relay present
    • Breakers manual synchro-switch is closed
    • Synchro-check circuit senses generator output voltage and phase sufficiently close to that of the bus and provides close permissive
  2. Diesel generator output breaker trips?
    • Engine trip
    • Loss of excitation
    • Generator overcurrent
    • -824 amps
    • Generator differential relay
    • Turbine trip after 1.5 seconds
    • -when the D/G is paralled to the bus
  3. D/G overcrank?
    • Shuts the ASMs off
    • 10 seconds
    • -must have >/= 10psig jacket water pressure
    • -must have >/= 120 rpm
  4. Design and normal operating range for D/G generator?
    Self cooled

    • Continuous rating
    • -2500kw @ 80% power factor

    • 2 hour rating
    • -2750kw
  5. What does a rise in reactive loading do to terminal voltage?
    • Would lower terminal voltage
    • -Auto voltage regulator would raise excitation until terminal voltage was at setpoint
  6. When would you not want to parallel the D/G with an outside source? and why?
    • If D/G is in unit
    • -D/G would assume a very large load
    • 0 droop on the governor
    • -possible generator overload and trip on overcurrent due to assuming reactive loads
  7. Explain the design bases of the emergency diesel generator system?
    • To provide on site power to reliably shutdown the plant and maintain it in a safe shutdown condition under all conditions, including DBA, upon loss of normal and/or standby power
    • -the D/Gs shall have sufficient capacity to supply minimum necessary engineered safeguards loads with 1 D/G
    • -each D/G shall have enough reserve to start and carry the largest single load that may be loaded by a control circuit malfunction
    • -each diesel shall be ready to load to full load IAW FSAR
    • -7 day supply of fuel oil for D/Gs shall be onsite
  8. What signals initiate the DBA sequencers?
    • Bus 1C or 1D undervoltage and SIS
    • D/G output breaker closed and load shed complete
  9. LCO 3.8.3.: Diesel fuel, lube oil, and starting air
    • LCO 3.8.3: For each D/G
    • -the stored diesel fuel oil, lube oil, and starting air subsystem shall be within limits
    • -both diesel fuel oil transfer systems shall be operable

    APP: When an associated D/G is required to be operable

    • If required action and associated comletion times not met or
    • stored diesel FO, LO, or starting air not withing limits
    • -declare inoperable immediately
  10. Operational design and normal operating range for D/G air start system?
    • Tank capacity provides sufficient air to the starting motor for 1 40 second start attempt with 90 psi to the ASM
    • -Normal air tank pressure >235 psig
  11. D/G overload ratings
    • 3 (187) differential relays connected to current transformers, one set on the neutral side, one set on the bus side of the 2400V EDG incoming breaker
    • -Trip the 2400V D/G breaker via lockout relay (186) and shutdown the diesel engine via the SDR

    • 3 inverse time overcurrent relays (151) connected to generator side of D/G 2400V breaker to protect D/G circuit from overloads
    • -trip breaker and D/G 2/3 logic @824 amps
  12. Negative consequences of closing D/G output breaker with unmatched voltage?
    Can assume excess reactive load and possibly experience an overcurrent
  13. What auto starts the EDG?
    • 2 levels of undervoltage protection
    • -loss of voltage function
    • --inverse time 77% rated voltage
    • -degraded voltage function
    • --93% of rated voltage for .65 seconds
  14. Recommended load ratings when synchronized to the bus?
    • Initially assume 50kw
    • Increase in 500 kw increments with a 5 minute wait
    • -these ensure no motoring
    • -allows engine to slowly warm up
  15. LCO 3.8.1.E.: 2 D/Gs inoperable actions
    Restore 1 D/G to operable status within 2 hours
  16. Consequences of operating the diesels on a loss of offsite power during the full load testing of the D/G?
    The D/G output breaker will trip to prevent overloading/damaging the D/G if a main generator trip occurs.
  17. Consequences of operating the D/Gs while under or overexcited?
    Excessive reactive load can result in generator high currents and overheating.
  18. When do you adjust the D/G manual voltage regulator?
    When unloaded
  19. Air compressor (D/G) power supplies?
    • G1-1-MCC1
    • G1-2-MCC2
  20. LCO 3.8.1.B one D/G inoperable actions?
    • Perform offsite source checks with in 1 hour and every 8 hours
    • Declare required feature supported by the inoperable D/G inoperable when its redundant required feature is inoperable with in 4 hours.
  21. What prevents the D/G output breaker from closing when bus is deenergized and diesel is operating?
    Overcurrent lockout relay 151x105
  22. Conditions to consider the D/G operable?
    • Jacket water >/= 90F
    • LO >/=90F (inoperable if >205F)
    • Both air train pressures >/= 95 psig but </= 175 psig
    • Air tank pressure >/= 215psig
    • SW available
    • Generator protective relays I/S
    • Engine protective relays I/S
    • Overspeed latched
    • Breaker in connect
    • Ventilation operable
    • -if < 85F one fan
    • -if >/= 85F two vent fans
    • -Not considered operable if powered from MCC-5, unless MCC-5 is powered from 1-1 DG
    • Voltage regulator in auto
    • Parallel/unit switch in unit
    • Crankcase doors installed
  23. LCO 3.3.5: Diesel Generator-undervoltage start
    LCO 3.3.5: 3 channels of loss of voltage function and three channels of degraded voltage function auto initiation instrumentation and associated logic channels for each D/G shall be operable

    APP: When associated D/G is required to be operable

    • Actions: One or more functions with 1 channel per D/G inoperable
    • -Enter applicable conditions and required actions for the associated D/G made inoperable by D/G-UV start instrumentation-IMMEDIATELY
  24. EDG field rheostat
    raises or lowers voltage
  25. Control power supplies for the D/Gs?
    • 1-1 D/G
    • -D-11A
    • 1-2 D/G
    • -D-21A
  26. Required conditions for automatic closure of an EDG output breaker?
    • Both incoming supply breakers are open
    • The generator overcurrent/differential lockout relay is reset
    • No bus overcurrent lockout relay present
    • Adequate EDG output voltage
    • Confirmed 2400V AC bus load shed
  27. Power supplies for fuel oil transfer pumps?
    • P-18A-MCC-8
    • P-18B-MCC-1
  28. D/G load limits?
    • 2500 kw continuous load
    • 2750 kw for 2 hours in a 24 hour period
    • Overcurrent alarm @ 752 amps
    • Breaker trip @ 824 amps
    • -these minimize engine wear
  29. Diesel generator automatic trips?
    • Overspeed 1060-1105 rpm
    • Low lube oil pressure <40 psig
    • Low jacket water pressure <10 psig for >45 seconds
    • Overcrank terminates start
    • Generator differential (current)
    • Generator overcurrent 824 amps
  30. Operational design and normal operating range of the diesel engines?
    • 18 cylinders, turbocharged, 4 cycle ALCO model 251F engines
    • rated @900rpm
    • overspeed trip @ 1060-1105rpm
  31. What signals initiate the normal shutdown sequencers?
    • BUS 1C or 1D undervoltage
    • EDG breaker closed and load shed complete
  32. Design and normal operating range of the D/G jacket water system?
    • Removes heat and maintains engine at approximately 120F
    • NOT 160-185F
    • Max temperature 195F
    • NOP 10-50psig
    • Normal flow 630-700 gpm
  33. Actions for a failed D/G cylinder leak test?
    • If moisture accumulation is greater than a fine mist
    • -record cylinder number
    • -record approximate amount and type of fluid
    • -initiate CR
    • -ensure engine not rotated until condition is evaluated
  34. Design and normal operating ranges of the D/G turbo charger?
    • Driven by exhaust, compresses air from 15-24psig and forces air into the cylinders
    • Normal exhaust temperature: 1200F
    • Maximum exhaust temperature: 1350F
  35. What is the purpose of the D/G governor setpoint switch?
    • Raises or lowers engine speed
    • Blue lights
    • -lit when @ highest or lowest speed
  36. How are the loads affected if the D/G fails to start or trips?
    • Sequencer will not activate
    • Undervoltage will initiate a load shed if the D/G trips
  37. Operational design and normal operating range of the D/G fuel oil system?
    • Provides a minimum 7 day onsite fuel oil supply for one D/G engine at full load
    • NOP: 40-60 psig
  38. Why is a D/G cylinder leak check required prior to a planned D/G start?
    To detect water leaks which can be an indication of a cracked block.
  39. If a D/G failed to start, what will prevent the actuation of the sequencers?
    The output breaker will not close
  40. Operational design and normal operating range of the D/G Lube oil system?
    • Provides lubrication and maintains the engine at approximately 120F
    • NOT-175-190F
    • Max temperature-200F
    • -if temperature >205F then the D/G is inoperable
    • NOP-80-90psig
    • Normal flow-320gpm
  41. Faulted bus protection?
    • Bus lockout protection initiates when the normal supply breaker trips on overcurrent
    • -diesel starts
    • -diesel generator output breaker closure is blocked by the overcurrent trip
  42. LCO 3.8.2.B required D/G inoperable actions
    • Suspend core alterations-IMMEDIATELY
    • Suspend movement of irradiated fuel-IMMEDIATELY
    • Initiate actions to suspend operations involving positive reactivity additions-IMMEDIATELY
    • Initiate actions to restore D/G to operable-IMMEDIATELY
  43. When is P-18A considered OPERABLE?
    • P-18A is considered operable in manual or automatic when the following conditions are met:
    • If in automatic then:
    •  The pump is valved into service
    •  The pump is able to be operated to move fuel
    •  The automatic emergency diesel generator day tank level switches for the operable diesel generator(s) are operable.
    • If in manual then:
    •  The pump is able to be valved into service
    •  The pump is able to be operated to move fuel
  44. When is P-18B considered operable?
    • P-18B can only be operated in manual and is considered operable when the following conditions are met:
    •  The pump is able to be valved into service
    •  The pump is able to be operated to move fuel
  45. When is the fuel oil transfer system considered inoperable?
    The fuel transfer system for a given diesel generator is considered inoperable when unable to perform the automatic level control function or fill function for the engine belly tank or for the day tank.
  46. How is generator load affected if the voltage regulator is placed from Auto to Manual when the EDG is loaded and paralleled to a bus?
    The Auto regulator will adjust the output voltage depending on load (real and reactive) to hold voltage at a constant value.  The manual voltage regulator does NOT follow the setting of the Auto regulator.  If the manual regulator was not adjusted to 2400 VAC during surveillance procedure MO-7 it could be at a significantly different value than the Auto regulator at the time of transfer.
  47. Why is the generator load reduced to only 50 KW prior to opening the generator output breaker?
    Ensures EDG is not motoring. Load is lowered to 50KW to minimize breaker current interruption
  48. If the D/G 1-1 (D/G 1-2) auto start/load was intentionally disabled by cutting out Relay 127-7 (127-8) to support Bus 1C (1D) outage.What actions will occur when undervoltage relay 127-7 (127-8) is reset during EDG startup?
    EDG output breaker will automatically close and the appropriate sequencer will start.
  49. The NCO-Turbine has placed the Parallel/Unit selector switch for EDG 1-2 in the PARALLEL position.  What effect does this have on EDG operability?
    Renders it inoperable. (SOP 22, 4.2.), Technical Specification SR Basis
  50. How many gallons of fuel oil is a 6 day supply?
    28,592 gallons
  51. How many gallons of Lube oil is considered a 6 day supply?
    268 gallons